[net/dns] Serve requests from HOSTS file if possible.

net/dns/dns_test_util.h

Index: net/dns/dns_test_util.h
diff --git a/net/dns/dns_test_util.h b/net/dns/dns_test_util.h
index 8d8c0a6d4b4b2bd24e02139b2b35c8ad24aad331..00867f8be38e5f78d3061b55bba061d680c009e8 100644
--- a/net/dns/dns_test_util.h
+++ b/net/dns/dns_test_util.h
@@ -7,6 +7,7 @@
 #pragma once
 
 #include "base/basictypes.h"
+#include "base/memory/scoped_ptr.h"
 #include "net/dns/dns_protocol.h"
 
 namespace net {
@@ -156,6 +157,10 @@ static const char* const kT3IpAddresses[] = {
 static const char kT3CanonName[] = "www.l.google.com";
 static const int kT3TTL = 0x00000015;
 
+class DnsClient;
+// Creates mock DnsClient for testing HostResolverImpl.
+scoped_ptr<DnsClient> CreateMockDnsClient();
+
 }  // namespace net
 
 #endif  // NET_DNS_DNS_TEST_UTIL_H_